A variety of types of medical devices are used for chronic, e.g., long-term, provision of therapy to patients. As examples, pulse generators are used for chronic provision of cardiac pacing and neurostimulation therapies, and pumps are used for chronic delivery of therapeutic agents, such as drugs. Typically, such devices provide therapy continuously or periodically according to parameters, e.g., a program comprising respective values for each of a plurality of parameters, specified by a clinician.
In some cases, the patient is allowed to activate and/or modify the therapy. For example, the symptoms, e.g., the intensity of pain, of patients who receive spinal cord stimulation (SCS) therapy may vary over time based on the activity level or posture of the patient, the specific activity undertaken by the patient, or the like. For this reason, a patient who receives SCS therapy from an implantable medical device (IMD), e.g., an implantable pulse generator, is often given a patient programming device that communicates with his IMD via device telemetry, and allows the patient to activate the neurostimulation and/or adjust the intensity of the delivered neurostimulation.
It is advantageous to associate patient therapy adjustments with one or more measurable parameters. After this association is made, a device may automatically deliver therapy to the patient according to those adjustments whenever the one or more parameters are detected. U.S. patent application Ser. No. 11/607,454 entitled “Closed-Loop Therapy Adjustment” filed Dec. 1, 2006, assigned to the assignee of the current disclosure, and which is incorporated by reference herein in its entirely, describes techniques for detecting a value of a sensed patient parameter, and automatically delivering therapy to a patient according to recorded therapy adjustment information previously associated with the detected value. According to these techniques, a therapy adjustment is received from the patient or other user and, in response to the adjustment, a sensed value of a patient parameter is stored with the therapy information determined based on the adjustment. The association may be made automatically or after user confirmation. Therapy may then be delivered according to the associated therapy information whenever the parameter value is subsequently detected. In this manner, as an example, a medical device that delivers therapy to the patient may “learn” to automatically adjust the therapy in the manner desired by the patient as the sensed parameter of the patient changes.